The Lead

Taking our understanding of quantum matter to new levels, scientists at Los Alamos National Laboratory are exposing high-temperature superconductors to very high magnetic fields, changing the temperature at which the materials become perfectly conducting and revealing unique properties of these substances.

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Using ultracold atoms as a stand-in for electrons, a Rice Univ.-based team of physicists has simulated superconducting materials and made headway on a problem that's vexed physicists for nearly three decades. The research was carried out by an international team of experimental and theoretical physicists and appears online in Nature. The work could open up a new realm of unexplored science.

Scientists discovered in 1937 that liquid helium-4, when chilled to extremely low temperatures, became a superfluid that could leak through glass, overflow its containers or eternally gush like a fountain. Future Nobel laureate Lev Landau came along in 1941, predicting that superfluid helium-4 should contain an exotic, particle-like excitation called a roton.

Scientists have demonstrated a nanoscale memory technology for superconducting computing that could hasten the advent of an urgently awaited, low-energy alternative to power-hungry conventional data centers and supercomputers. In recent years, the stupendous and growing data demands of cloud computing, expanded Internet use, mobile device support and other applications have prompted the creation of large, centralized computing facilities.

A new type of nanowire crystals that fuses semiconducting and metallic materials on the atomic scale could lay the foundation for future semiconducting electronics. Researchers at the Univ. of Copenhagen are behind the breakthrough, which has great potential. The development and quality of extremely small electronic circuits are critical to how and how well future computers and other electronic devices will function.

Theorists and experimentalists working together at Cornell Univ. may have found the answer to a major challenge in condensed matter physics: identifying the smoking gun of why “unconventional” superconductivity occurs, they report in Nature Physics.

Massachusetts Institute of Technology researchers have discovered a new mathematical relationship—between material thickness, temperature and electrical resistance—that appears to hold in all superconductors. The result could shed light on the nature of superconductivity and could also lead to better-engineered superconducting circuits for applications like quantum computing and ultra-low-power computing.

An experiment at SLAC National Accelerator Laboratory provided the first fleeting glimpse of the atomic structure of a material as it entered a state resembling room-temperature superconductivity—a long-sought phenomenon in which materials might conduct electricity with 100% efficiency under everyday conditions.

A team of scientists has discovered an unusual form of electronic order in a new family of unconventional superconductors. The findingestablishes an unexpected connection between this new group of titanium-oxypnictide superconductors and the more familiar cuprates and iron-pnictides, providing scientists with a whole new family of materials from which they can gain deeper insights into the mysteries of high-temperature superconductivity.

A study at the SLAC National Accelerator Laboratory suggests for the first time how scientists might deliberately engineer superconductors that work at higher temperatures. In their report, a team of researchers explains why a thin layer of iron selenide superconducts at much higher temperatures when placed atop another material, which is called STO for its main ingredients strontium, titanium and oxygen.

Researchers studying iron-based superconductors are combining novel electronic structure algorithms with the high-performance computing power of the U.S. Dept. of Energy’s Titan supercomputer at Oak Ridge National Laboratory to predict spin dynamics, or the ways electrons orient and correlate their spins in a material.

A research team led by a Brown Univ. physicist has produced new evidence for an exotic superconducting state, first predicted a half-century ago, that can arise when a superconductor is exposed to a strong magnetic field. This new understanding of what happens when electron spin populations become unequal could have implications beyond superconductivity.

Research by an international team of scientists has uncovered a new, unpredicted behavior in a copper oxide material that becomes superconducting at relatively high temperatures. This new phenomenon presents a challenge to scientists seeking to understand its origin and connection with high-temperature superconductivity. Their ultimate goal is to design a superconducting material that works at room temperature.

Computer chips with superconducting circuits would be 50 to 100 times as energy efficient as today’s chips, an attractive trait given the increasing power consumption of the massive data centers that power Internet sites. Superconducting chips also promise greater processing power: Superconducting circuits that use so-called Josephson junctions have been clocked at 770 GHz, or 500 times the speed of the chip in the iPhone 6.

Mazhar Ali, a fifth-year graduate student in the laboratory of Bob Cava, the Russell Wellman Moore Professor of Chemistry at Princeton Univ., has spent his academic career discovering new superconductors, materials coveted for their ability to let electrons flow without resistance. While testing his latest candidate, the semimetal tungsten ditelluride (WTe2), he noticed a peculiar result.

Imagine being able to tune the properties of a solid material just by flashing pulses of light on it. That is one potential payoff of electrons and atoms interacting with ultrashort pulses of light. The technology of ultrafast spectroscopy is a key to understanding this phenomenon and now a new wrinkle to that technology, observations of electron self-energy, has been introduced by Lawrence Berkeley National Laboratory researchers.

A new frontier for studying 2-D matter is provided by planar collections of electrons at the surface of transition-metal-oxide (TMO) materials, in which high electron densities give rise to interactions that are stronger than in semiconductors. Scientists hope to find exotic phenomena in these highly-interactive electron environments and one of the leaders in this effort is James Williams, a new fellow at the Joint Quantum Institute.

Research from North Carolina State Univ. shows that a type of modified titania, or titanium dioxide, holds promise as an electrical insulator for superconducting magnets, allowing heat to dissipate while preserving the electrical paths along which current flows. Superconducting magnets are being investigated for use in next-generation power generating technologies and medical devices.

Physicists studying the effects of embedding magnetic spins onto the surface of a superconductor recently report that the spins can interact differently than previously thought. This hybrid platform could be useful for quantum simulations of complex spin systems, having the special feature that the interactions may be controllable, something quite unusual for most condensed matter systems.

New measurements of atomic-scale magnetic behavior in iron-based superconductors by researchers at Oak Ridge National Laboratory and Vanderbilt Univ. are challenging conventional wisdom about superconductivity and magnetism. The study provides experimental evidence that local magnetic fluctuations can influence the performance of iron-based superconductors, which transmit electric current without resistance at relatively high temperatures.

Thanks to a $1.5 million innovation award from the Gordon and Betty Moore Foundation, Rice Univ. physicist Emilia Morosan is embarking on a five-year quest to cook up a few unique compounds that have never been synthesized or explored. Morosan is no ordinary cook; her pantry includes metals, oxides and sulfides, and her recipes produce superconductors and exotic magnets.

The search for zero-resistance conductors that can operate at realistic temperatures has been frustrated by the inability to understand high-temperature superconductors, particularly their magnetic structure. Researchers have done this at the atomic scale for the first time with a so-called strongly correlated electron system of iron telluride. Previously, magnetic information was provided by neutron diffraction, which is imprecise.

Physicists have identified the “quantum glue” that underlies a promising type of superconductivity—a crucial step towards the creation of energy superhighways that conduct electricity without current loss. The research, published online in the Proceedings of the National Academy of Sciences, is a collaboration between the Univ. of Illinois at Chicago, Cornell Univ. and Brookhaven National Laboratory.

Using a new type of large-scale magnet conductor, scientists in Japan have recently achieved an electrical current of 100,000 A, a world record. The conductor, which was built using yttrium-based high-temperature superconducting tapes for high mechanical strength, is a prototype for using in a future fusion reactor.

When a superconductor is exposed to a magnetic field, a surface current creates a magnetic field that cancels the field inside the superconductor. This phenomenon, known as the Meissner-Ochsenfeld effect, was first observed in 1933. In a research first, scientists have succeeded in measuring an analogue of the Meissner effect in an optical crystal with ultracold atoms. This validates theoretical predictions dating back more than 20 years.

Using a scanning tunneling microscope to visualize the electronic structure of the oxygen sites within a superconductor, a Binghamton Univ. physicist and his colleagues say they have unlocked one key mystery surrounding high-temperature superconductivity. The team found a density wave with a d-orbital structure, which is a pattern new to this type of superconductor and they may be found in all cuprates.